[phobos] Time to get ready for the next release

[Jacob Carlborg]

On 24 apr 2011, at 18:03, Robert Jacques wrote:

> On Sun, 24 Apr 2011 07:33:30 -0400, Jacob Carlborg <doob at me.com> wrote:
>> On 23 apr 2011, at 23:20, Robert Jacques wrote:
>>> On Sat, 23 Apr 2011 16:06:35 -0400, Jacob Carlborg <doob at me.com> wrote:
>>>> On 23 apr 2011, at 17:32, David Simcha wrote:
>>>>> On 4/23/2011 11:24 AM, Jacob Carlborg wrote:
>>>>>> I think I would like to have something in the middle of strict and loose semantics. I would like that functions marked with @property have to be called like a field:
>>>>>> 
>>>>>> auto bar = foo.field;
>>>>>> foo.field = 3;
>>>>>> 
>>>>>> But functions not marked with @property still can be called without the parentheses:
>>>>>> 
>>>>>> foo.bar();
>>>>>> foo.bar;
>>>>> 
>>>>> Maybe there's been some misunderstanding, but actually this is what loose semantics means.  Loose semantics (at least as I understand them) mean stuff marked @property would not be callable using method syntax, and this rule would be used to disambiguate the corner cases, but nothing would change for stuff not marked @property.
>>>> 
>>>> Ok, then I probably misunderstood. What about:
>>>> 
>>>> writeln = "foo";
>>>> 
>>>> is that already fixed?
>>> 
>>> If by fixed, you mean doesn't compile, then yes, it's fixed. But this might be a quality of implementation issue, regarding method syntax and templates and not a true theoretical fix. Case in point: printf = "foo" works. However, while ugly, neither writeln = "foo" nor printf = "foo" are doing something the original author didn't intend. The greater violators (which actually caused bug reports/confusion) are those where the statements became nonsense, like math_function = 5 or obj.factory_method = 6.[1] Fixes for most of these issues exist: Not using the result from a strongly pure function should be an error, not matter how it's called. And const/immutable methods shouldn't be assignable, since you can't assign to a const or immutable variable. Static/free functions can't be marked const/immutable, but considering the only thing they can modify is global state, pure is equivalent. So neither strongly nor weakly pure functions should be assignable.
>> 
>> If writeln = "foo"; doesn't compile but printf = "foo"; does then I would consider it not fixed. The way I would want @property to behave is disallow bar = "foo"; for functions not marked with @property. But still allow functions not marked with @property to be callable without parentheses.
> 
> I have not heard this particular combination before; thank you. More choices are always appreciated. There are real, practical use cases for not- at property methods with write-only field semantics, which this would prevent. And between a real use case and a synthetic straw-man, I believe the use case should win. However, I am interested in any of the practical issues which inspired writeln = "foo", if you know of any.

I don't know if there is an issue with writeln = "foo" other than that it can be confusing and looks very odd.

> Also, this and another post have given me an idea: what if non- at property methods could be assigned to if and only if a valid 'getter' also existed. This would still 'fix' writeln = "foo" but be a less restrictive than an outright ban.

Hm, it sounds like a strange rule, I don't know, it could work.

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-- 
/Jacob Carlborg